(CNN)The number of liver transplants for Americans with alcohol-associated liver disease has steadily grown in recent years, prompting researchers to explore why this is and what the long-term prospects are for recipients.

Using 15 years of data collected by the United Network for Organ Sharing, which manages the organ transplant system in the United States, a group of scientists set out to analyze trends from 2002 through 2016.

Their findings, published Tuesday in the journal JAMA Internal Medicine, were that alcohol-associated liver disease — including alcoholic cirrhosis, alcoholic cirrhosis with hepatitis C and acute alcoholic hepatitis — has emerged as the leading reason for liver transplants in recent years.

Hepatitis C virus infection used to be the top reason for liver transplants, explained Dr. Norah Terrault, a hepatologist at the University of California, San Francisco, who co-authored the study. The advent of effective antiviral therapy, however, changed the equation.

There were 433 alcohol-associated liver disease transplants in 2002; by 2016, that number had nearly tripled to 1,253, Terrault said.

As the need for transplants for hepatitis C patients fell, a greater proportion of liver transplants went to patients with alcohol-related disease — accounting for 48% of the growth, the study showed.

But another important explanation for the increase, the study suggested, was a growing acceptance of early transplants for those with liver disease linked to alcohol use.

The six-month litmus test

In 1983, during the early yearsof liver transplantation, senior hepatologists — specialists in disorders of the liver, pancreas and gallbladder — suggested that before patients with alcohol-associated liver disease could be listed for a transplant, they should commit to six months of abstinence from alcohol, according to a commentary accompanying the new study.

The reasoning behind this was twofold, the commentary outlined. Six months of abstinence might allow the liver to stabilize, negating the need for a transplant. And a litmus test like this might address concerns about messaging.

If the public thought organs were being given to patients perceived to have a “self-inflicted disease,” said co-author Dr. Mack Mitchell, would they be less likely to sign on as donors? Would they balk and deem the recipients undeserving?

Experts “felt they needed to have something to offer society to show we were doing this in a responsible way,” said Mitchell, a hepatologist at University of Texas Southwestern Medical Center in Dallas, who was part of the liver transplant team at Johns Hopkins in ’80s. The six-month rule, followed at least initially, served as their answer.

What they found in the ensuing 30-plus years, however, was that the six-month timeframe was arbitrary. Not only did it fail to predict success rates, it left out those patients who didn’t have six months to wait for new livers, namely those with acute alcoholic hepatitis, Mitchell said.

A 2011 report out of France and Belgium, referenced in both the new study and the commentary, focused on those with acute alcoholic hepatitis. With no mandatory pre-transplant sobriety period, researchers found, these transplant recipients enjoyed excellent outcomes and survival rates.

That trial probably helped shift attitudes about transplant for alcohol-associated liver disease in the United States, the new study said, as the proportion of transplants grew for these recipients across the board. Some regions in the organ transplant system saw greater growth than others, however, indicating shifts in attitude varied and suggesting that it may be time to create a national policy, said Terrault, the study co-author.

Recipients by the numbers

For the new study, researchers took the national organ transplant data and adjusted it to compare adult transplant recipients who had only alcohol-associated liver disease with those who clearly had no alcohol-associated problems — excluding all others who might muddy the analysis.

Of the nearly 33,000 recipients of liver transplants they looked at over the 15-year period, more than 9,400 had alcohol-related liver disease.

The post-transplant outcomes between the two groups were largely comparable in the first five years. After five years, survival for patients with alcohol-associated liver disease was 11% lower than for their counterparts, the study showed.

But that could be due to lack of attention and resources given to transplant recipients as time goes on, experts said.

Without knowing exactly why the long-term survival rate dipped, Terrault said, “we need to look at ways to improve alcohol-related liver disease by reducing complications like relapse and deaths due to malignancy and infection.”

Deciding who is worthy

There are more than 3,700 candidates on the US liver transplant wait list who have alcohol-associated liver disease, according to data provided by the United Network for Organ Sharing.

The network monitors statistics but does not dictate medical care, impose policies or determine who can be listed for a transplant, explained its chief medical officer, Dr. David Klassen. All of that is left to the transplant centers, their doctors and the teams who carefully evaluate patients.

For people who might still prejudge who is worthy of a new liver, commentary co-author Mitchell asked skeptics to consider this: Not all heavy drinkers develop liver injury or damage; only about 20% do, he said. Some carry a genetic risk, while most don’t.

“Do you blame people born with the wrong genes or not?” Mitchell asked.

Just as he hopes we won’t punish people for their genetics, he said, we need to think about whether we punish people based on their lifestyles.

“Should you say someone who smokes cigarettes shouldn’t receive a lung transplant? Should someone who ate too much never receive a heart transplant?” he asked.

“People today are living long periods of time and eventually dying from things that have a significant lifestyle component,” Mitchell said.

Focusing on just one aspect of a person’s life, he warned, can cross the line of what is fair and socially just.